JPS594614B2 - How to control the number of hot and cold water machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating and cooling system configured by connecting a plurality of water coolers/heaters in parallel, and particularly to a technique for controlling the number of water coolers/heaters connected in parallel according to the load.

One method of configuring a heating and cooling system is to connect several small unit-type water coolers/heaters in parallel depending on the size of the load to achieve a desired capacity.

In such a system, there is no problem if 100% load is requested from the water cooler/heater, but if the required load becomes small, the return from the load such as the fan coil unit during cooling operation may occur. When the temperature of the cold water coming in drops to a temperature close to the outlet temperature of the water cooler/heater, the required load can be met with a small number of water coolers without having to run all of the water coolers in parallel. The problem is whether to control the number of stopped machines.

Conventional systems generally have a configuration as shown in FIG.

To make it easier to understand, we will explain what happens during cooling operation. Therefore, it is assumed that the water chiller/heater is an absorption type and acts as an air conditioner, and that two chiller/hot water machines and two loads are installed. .

In FIG. 1, the hot and cold water machines 2 and 4 are piped in parallel at their inlets and outlets, with the outlet connected to a cold and hot water reservoir 6 and the inlet connected to another cold and hot water reservoir 10 via a pump 8.

The hot and cold water reservoir 6 is connected to a load 16.18 via pumps 12 and 14, respectively, and to the cold and hot water reservoir 10 via a solenoid valve 20.22.

A bypass path including a solenoid valve 24 is provided between the cold and hot water reservoirs 6 and 100.

The operation/stopping control of the cold/hot water machines 2 and 4 is performed by detecting the temperature at the cold/hot water machine inlet using a temperature detector installed in the cold/hot water reservoir 10 or the cold/hot water return pipe between the cold/hot water reservoir 10 and the pump 8, for example. The water cooler/heater is sequentially controlled according to a predetermined order of operation and stop based on signals from a device that generates step signals in response to the operation.

On the load side, the pump 12.14 and the solenoid valve 20,
22, and in some cases, a solenoid valve 24 is operated to control the temperature.

The present invention attempts to provide a new proposal in which temperature control on the load side is performed independently using a temperature switch as in the past, but control of the number of water coolers and hot water machines is performed using a separate control.

A preferred embodiment of the present invention illustrated in FIGS. 2 and 3 will be described in detail below.

FIG. 2 shows a heating and cooling system constructed by using the flow rate control method according to the present invention in place of the conventional temperature-controlled heating and cooling system.

According to FIG. 2, the load 16.18 and the solenoid valve 20.2
The return cold and hot water that has passed through 2 is led to the cold and hot water reservoir 10 via one water volume measuring device 26, and this water volume measuring device 2
The number of hot and cold water machines is controlled according to the amount of water obtained in step 6.

The signal representing the amount of water is input to the step signal generator 28, which generates a step signal corresponding to the detected amount of water, and this step signal controls the ignition device 30 of the cold/hot water machine 2.4 and the cold/hot water pump 8. The number of water machines is controlled.

For example, if this entire system is in operation, all the water coolers 2 and 4 and all the pumps 8°12.14 are in operation, and all the solenoid valves 20 except the bypass solenoid valve 24 are in operation.
．． 22 is open.

At this time, in loads 16 and 18, the operation of the fan is independently controlled by a temperature switch, and the indoor temperature is adjusted by adjusting the amount of cold air passing through the heat exchanger.

Here, for example, when the load 18 no longer requires cooling, that is, when the cooling operation switch of the load 18 is artificially turned off, the pump 14 is stopped and the solenoid valve 22 is closed.

At the same time, the solenoid valve 24 is opened to bypass the excess cold water supplied from the cold/hot water reservoir 6 to the cold/hot water reservoir 10.

At this time, the water measuring device 26 detects that the amount of cold water in the return pipe has reached 50 cm, and the step signal generator 28 causes the first-ranked cold/hot water machine to switch to ? q For example, the operation of the water cooler/heater 2 is stopped, and only the water cooler/heater 4 is operated for cooling.

At this time, since cold water is not primarily produced in the stopped water cooler/heater 2, there is no difference in temperature between its inlet and outlet, and the temperature of the cold water in the cold/hot water reservoir 6 increases as it mixes with the cold water generated by the cold/hot water machine 4. Since the load 16 is the only part of the entire system that undergoes heat exchange (thermal energy absorption), the response time to obtain the desired cold water is slightly delayed, and the amount of cold water supplied to the cold/hot water reservoir 6 rises slightly; It has no effect on indoor temperature control.

The second embodiment of the present invention shown in FIG. 3 takes into consideration the delay in response time and rise in cold water temperature in the embodiment of FIG.

According to FIG. 3, one water supply pump is installed for each cold/hot water machine 2.4.

A further feature of this embodiment is that by eliminating the load pump, equipment costs and operating costs are reduced.

In this second embodiment, the temperature adjustment of the load itself is controlled by whether or not to operate the fan using a temperature switch, as in the conventional case.

For example, if the load 18 is to be completely stopped, by turning off the cooling operation switch of the load 18, the solenoid valve 22 is closed, and at the same time, the bypass solenoid valve 24 is opened.

At this moment, the two water chillers 2 and 4 and their associated pumps 32 and 34 are still operating, and the heat-exchanged chilled water goes to the load 16, and the surplus is passed through the solenoid valve 24 to the cold and hot water. It is bypassed to water reservoir 10.

Here, the water amount is detected by the water amount measuring device 26 installed in the return pipe, and in the case of FIG. The water cooler/heater in the first order, for example, the water cooler/heater 2 and the associated pump 32 are stopped.

Although the present invention has been described above regarding cooling operation, flow rate control is similarly possible during heating operation.

Also, as a typical example, two chiller/heater machines and two loads are shown, but in reality, a larger number of loads are often connected, and the number of chiller/heater machines will be set according to the size of the load. .

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional temperature-controlled heating and cooling system, FIG. 2 is a diagram showing a first embodiment of a flow rate-controlled heating and cooling system according to the present invention, and FIG. 3 is a diagram showing a second embodiment of the present invention. FIG. 2.4...Cold/hot water machine, 6,10...Cold/hot water reservoir, 8.12,14...Pump, 16.1
8... Load, 20..., 22, 24...
Solenoid valve, 26...Water flow meter, 28...
・Step signal generator, 30...Ignition device, 3
2,34...Pump.

Claims (1)

[Claims] 1 In a method for controlling the number of cold/hot water machines in which multiple cold/hot water machines are connected in multiple stages and a specific cold/hot water machine is operated or stopped according to the size of the load, the cold/hot water return pipes from each load are collected. A method for controlling the number of cold/hot water machines, comprising: measuring the amount of cold/hot water returned after the water has been drained, and operating or stopping the cold/hot water machines according to a predetermined order of operation or stop according to the measured water amount.